1. Field of the Invention
The present invention relates to an indentation hardness tester.
2. Description of the Prior Art
Heretofore there has been proposed an indentation hardness tester which will hereinbelow be described with reference to FIGS. 3 and 4.
The conventional indentation hardness tester has a case 1 as a stationary part. The case 1 has a bottom panel 2 extending horizontally, a rear panel 3 extending upwardly from the rear edge of the bottom panel 2, a lower front panel 4 extending upwardly from the front edge of the bottom panel 2 to a height shorter than that of the rear panel 3, a panel extending rearwardly from the upper edge of the lower front panel 4 and shorter than the bottom panel 2 in the front-to-back direction, a central front panel 6 extending upwardly from the rear edge of the panel 5, a panel 7 extending forwardly from the upper edge of the central front panel 6 in opposing relation to the panel 5, an upper front panel 8 extending upwardly from the front edge of the panel 7, and a top panel 9 extending between the upper edge of the upper front panel 8 and the upper edge of the rear panel 3.
Reference numeral 11 indicates a specimen table unit, which includes a vertical moving lever driver 12 which is fixedly mounted on the bottom panel 2 in the space defined by the bottom panel 2 and the panel 5 of the case 1, a vertically moving lever 13 which extends upward from the vertical moving lever driver 12 through a window 5a made in the panel 5 and is vertically moved up and down by the vertical moving lever driver 12, and a specimen table 14 mounted on the top of the vertically moving lever 13. In this instance, the specimen table 14 has a horizontal specimen bearing surface 14a on which a specimen 20 is paced from above, and the table 14 is movable back and forth with the specimen bearing surface 14a held horizontal.
Reference numeral 32 denotes a fulcrum bearing member, which is formed by a plate member which has a top surface 32a extending horizontally and a fulcrum bearing surface 32b formed by a laterally extending V-shaped groove cut in the top surface 32a, as shown in detail in FIG. 4. The fulcrum bearing member 32 is fixedly mounted on the central front panel 6.
Reference numeral 41 denotes a balance, which has a centrally-disposed downward fulcrum 42 formed by a V-shaped projecting piece which is received by the fulcrum bearing surface 32b of the fulcrum bearing member 32. The balance 41, with the fulcrum 42 received by the fulcrum bearing surface 32b of the fulcrum bearing member 32, is extended forwardly of the central front panel 6 through a window 6a made therein and carries at the extended free end an indenter 43 located close to the specimen table 14 and a test load weight 44. Further, the balance 41 is extended rearwardly in the case 1 and carries at the extended free end a horizontal balancing weight 45. The weight and position of the horizontal balancing weight 45 on the balance 41 are determined so that the balance 41 may remain level in the state in which the test load weight 44 is not mounted on the free end portion of the balance 41 near the indenter 43. The balance 41 further includes a lever 46 which extends downward from the position of the fulcrum 42 through a through hole 32c (shown in FIG. 4) made in the fulcrum bearing member 32 and by which the center of gravity of the balance 41 is located at the tip end portion of the fulcrum 42. The lever 46 carries a vertical balancing weight 47. The balance 41 further has a pin 48 planted rearwardly on the free end portion on the side opposite from the indenter 43.
Reference numeral 51 identifies a balance control, which is disposed in the case 1 between the rear panel 3 and the central front panel 6 thereof and includes an actuating lever driver 52 fixed to the rear panel 3 and an actuating lever 53 which extends upwardly from the actuating lever driver 52 and is driven up and down by the driver 52. The actuating lever 53 has in its free end portion a vertically elongated hole 54 which has loosely fitted thereinto the pin 48 of the balance 41.
Reference numeral 61 denotes a microscope which is optical means for observing the specimen 20. The microscope 61 includes an eyepiece lens 62 which is mounted on the upper front panel 8 of the case 1 in such a manner that its optical axis may extend aslant from the front of the panel 8 and into the case 1 through a window 8a made in the panel 8, an objective lens 63 which is mounted on the panel 7 of the case 1 in such a manner that its optical axis may extend vertically from under the panel 7 and into the case 1 through a window 7a made in the panel 7, and an optical system 65 which includes a reflector 64 mounted on the panel 7 in the optical path between the eyepiece lend 62 and the objective lens 63. In this instance, the objective lens 63 is mounted on the panel 7 at a position forwardly of the forward free end portion of the balance 41 so as to keep the optical path of the objective lens 63 under the panel 7 from being intercepted or blocked by the above-said free end portion of the balance 41.
With such a conventional indentation hardness tester as described above, the actuating lever 53 of the balance control 51 is normally held down by the actuating lever driver 52, and consequently, the upper inner face of the elongated hole 54 engages the pin 48 of the balance 41, causing the balance 41 to slightly turn about the fulcrum 42 received by the fulcrum bearing member 32 against a test load by the test load weight 44. On the other hand, the vertically moving lever 13 is held down by the vertically moving lever driver 12, and consequently, the specimen table 14 remains at its lowered position. Further, the specimen table 14 stays at its rear position.
When placing the specimen 20 on the specimen table 14 of the specimen table unit 11 and then actuating the vertically moving lever driver 12 of the specimen table unit 11, the vertically moving lever 13 and consequently the specimen table 14 moves up to a position where the specimen 20 lies right below the indenter 43 in adjacent but spaced relation thereto. Then, operating the actuating lever driver 52 of the balance control 51, the actuating lever 53 moves up, and hence the pin 48 of the balance 41 disengages from the elongated hole 54 of the actuating lever 53 and the balance 41 turns about the fulcrum 42 received by the fulcrum bearing member 32 owing to the test load by the test load weight 44, making an indentation in the specimen 20 by the indenter 43 with the test load based on the test load weight 44.
After an impression has been made in the specimen 20 as mentioned above, the actuating lever 53 will automatically return to its initial position when the actuating lever drive 52 of the balance control 51 is operated in a direction reverse to that in which to make the indentation in the specimen 20. As the result of this, the elongated hole 54 made in the actuating lever 53 engages the pin 48 of the balance 41 and presses it downward, by which the balance 41 is caused to turn about the fulcrum 42 received by the fulcrum bearing member 32 against the test load by the test load weight 44, thus lifting the indenter 43 off the specimen 20.
After the indenter 43 has been brought up from the indented specimen 20 as referred to above, the specimen 20 can be brought to a position just under the objective lens 63 of the microscope 61 when the specimen table 14 of the specimen table unit 11 is moved forward. Thus, the size of the indentation made in the specimen 20 can be measured by the microscope 61 through the eyepiece lens 62, the optical system 65 including the reflector 64 and the objective lens 63. Based on the thus measured size of the indentation and the test load by the test load weight 44, the hardness of the specimen 20 can be detected.
After the size of the indentation made in the specimen 20 has been measured as mentioned above, the vertically moving lever 13 will move down when the specimen table 14 is brought back to its initial position and then the vertically moving lever driver 12 is operated in a direction reverse to that in which to raise the vertically moving lever 13. Consequently, the specimen table 14 lowers to its initial position, where the specimen 20 can be removed from the table 14.
As will be seen from the above, it is possible, with the conventional indentation hardness tester of FIGS. 3 and 4, to measure the hardness of the specimen 20 on the basis of the size of the indentation made in the specimen 20 and the test load applied thereto when the indentation was made.
In the case of the conventional indentation hardness tester depicted in FIGS. 3 and 4, since the fulcrum bearing member 32 is fixedly mounted on the central front panel 6 of the case 1 which is a stationary part, and since the microscope 61 as optical means for specimen observation use, including the objective lens 63, is fixedly mounted on the case 1, the specimen 20 after being indented must be brought to a position just under the objective lens 63 of the microscope 61 by moving the specimen table 14 forward. In this case, if the specimen table 14 lies at a position where the optical axis of the objective lens 63 exactly passes through the center of the indentation made in the specimen 20, then the center of the indentation lies at the center of the visual field of the microscope 61 and the size of the indentation can be measured precisely. In practice, however, it is difficult to place the specimen 20 at a predetermined position on the specimen table 14 with high precision, and hence it is necessary to effect fine positioning control of the specimen table 14 by moving it back and forth or to right or left little by little so that the table 14 may lie at the position where the optical axis of the objective lens 63 exactly passes through the center of the indentation made in the specimen 20.
Thus, it is seriously cumbersome, in the prior art indentation hardness tester, to bring the indented specimen 20 to the position just under the objective lens 63 of the microscope 61 by moving the specimen table 14. Moreover, much skill and time are needed to bring the specimen table 14 to the above-mentioned position with high accuracy, besides it is necessary to prepare, as the specimen table 14, an expensive table which can be moved little by little.